George Hardcastle, county councillor for Aston, said: “It’s disgusting – absolutely disgusting. This hospital is supposed to be serving the community but it’s letting the community down.

“We have elderly and vulnerable people who have been pencilled in to have treatment there and now what are they supposed to do?

“These patients are already in need of treatment and shouldn’t have to travel any further than they need to.”

The investigation involves North Wales Police, Healthcare Inspectorate Wales, Flintshire County Council and Betsi Cadwaladr Health Board (BCHB) was launched in August.

The hospital has two wards – both are under investigation. No members of staff have been suspended from duty while the investigation is carried out: instead those members of staff in question have been given other duties to perform.

BCHB said concerns had been raised around “issues of care, dignity and respect of patients”. “The investigation into the concerns previously raised is now nearing completion.”

Health bosses said the investigation and pressure on staff numbers had left them struggling to run the ward safely.

A BCHB spokesman spokesman said: “This has been caused by a combination of retirements, long-term sickness and a number of staff being on restricted duties while an investigation into standards of care is completed.

“Twelve beds had to be taken out of use over the Christmas period as it was not possible to ensure safe staffing numbers on every shift, even by trying to obtain bank and agency staff.

“Although every effort is being made to recruit extra staff, the pressures on staffing are continuing at present. This is at a time when the emergency demand on the health service means the hospital is looking after frail patients with complex needs.

“On Friday we decided to concentrate all the available staff to work on one ward to make sure all shifts can be safely covered. This has meant the number of available beds in the hospital has temporarily been reduced to 24.”

While the ward is closed hospital bosses have grabbed the chance to carry out planned maintenance work.

The spokesman said: “While the Gladstone ward is closed, the opportunity is being taken to renew the flooring and carry out other refurbishment work that was due. This work could not be carried out while the area is in use so would have required the ward to be closed for a period anyway.”

It remains unclear when Gladstone will have enough staff on rota to start functioning again or where patients will be treated in the meantime.

The spokesman added: “The ward will reopen as soon as we have sufficient staff to ensure that all shifts can be covered safely across both wards.”

Interviews for vacant positions left by those retiring are due to be carried out next week.

Health unions said they were aware of the problems the hospital was battling. Donna Hutton, regional organiser for North Wales health branch of Unison, said the union was keeping an eye on developments on Gladstone Ward.